Wireless devices typically adjust the amount of power they deliver to the transmit antenna of the wireless device. For example, when a cellular phone is close to a base station, less power is required than when the cellular phone is farther away from the base station. In this example, the base station may dynamically instruct the cellular phone to go to a certain transmit power level based on the signal strength being received by the base station.
However, circumstances local to the cellular phone may change since the last base station instruction. For example, the user may change his/her grip on the cellular phone and thereby create path loss due to shading that affects the signal. In order to compensate for this type of situation, the cellular phone may also make adjustments to its transmit power level. However, without information from the base station, the cellular phone cannot measure its transmit path loss. Instead, the cellular phone may measure its receive signal strength to estimate its transmit path loss and adjust its transmit power accordingly.
If the receive antenna in the handset is physically located near the transmit antenna, this estimation technique works well. However, if the receive antenna in the handset is not physically located near the transmit antenna, this estimation may be inaccurate. An improved method of estimating the spatial mode (e.g., orientation and hand grip) of wireless devices is needed. This improved estimation of spatial mode may be used, among other things, to more accurately determine transmit antenna gain.